Sorry, and also do i need to dual boot?

since i have 2 harddisk
1. Winxp
2. Mac os

if i need, do i need to format the winxp to fat32 to dual boot for mac osx?

and also to install mac osx in the new harddisk, do i need to format it to fat32 first? or i jus need to initialize the harddisk to install mac osx.